Integrated circuit (IC) cards typically include a substrate and a circuit formed in the substrate. The substrate 20 with the predefined full-size (1FF) IC card format is shown in FIG. 1, and the circuit 3 may be used as a card for certain applications, which comply with the standard ISO/IEC 7810:2003, for example, as a credit card or cash point card. For other applications, the circuit is detached from the card, together with a sector of predefined form and size, for example, the predefined form and size equivalent to the Mini-SIM (2FF), Micro-SIM (3FF) or Nano-SIM (4FF) IC card formats (FIG. 1).
Essentially, the IC in the sector forms a small-size card which may be used for specific applications. For example, in the 2FF format (ISO/IEC 7810:2003 specification), the card may be used with most cellular phones. In the 3FF format (ETSI TS 102 221 V9.0.0 specification), it may be used with certain smart phones, such as the iPhone 4; and in the 4FF format (ETSI TS 102 221 V11.0.0 specification), it may be used in the more recent iPhone 5. The formats differ in terms of surface dimensions and/or thickness.
The substrate with the 1FF format has a size of 85.6 mm×53.98 mm×0.76 mm and has, formed in it, a number of pre-incisions corresponding to the sector with 2FF format (25 mm×15 mm×0.76 mm), the sector with 3FF format (15 mm×12 mm×0.76 mm) or the sector with 4FF format (12.3 mm×8.8 mm×0.67 mm), for removal of the sectors. Such cards may be helpful because they incorporate four different formats, i.e. 1FF, 2FF, 3FF and 4FF.
However, they may have several drawbacks, mainly associated with the production complexity and costs and certain defects, which occur when removing the sectors with 2FF, 3FF or 4FF format from the card. In particular, as can be understood from the dimensions indicated above, the 4FF format is characterized not only by a smaller surface area compared to other formats, but also by a smaller thickness, which may require machining of the substrate.
A first technique includes starting with a substrate having a thickness, which is substantially the same as the thickness of the formats 1FF, 2FF and 3FF (0.76 mm), and scraping a portion of the substrate in which the thinner sector (0.67 mm), with format 4FF thickness, is formed for integration of the circuit. After scraping, the pre-cut lines are formed in the substrate to delimit the 2FF, 3FF and 4FF sectors.
In this method, it may be difficult to perform a precise scraping operation, involving precisely only the 4FF sector. Moreover, incision of the pre-cut lines may be complicated by the different thickness of the substrate. Moreover, performing pre-cut lines before scraping may result in breakage of the lines during scraping.
This technique may give rise to a large number of defective cards during production, or to defects in the final product, resulting in difficult extraction of the sectors with 2FF, 3FF and 4FF format. This may be problematic in the case where a sector, for example, 4FF format sector, becomes detached, even only partially from the card, despite the fact that the user intends to detach another sector, for example, a sector with 3FF or 2FF format.
Another technique may include injection-molding, namely the injection of a material in a mold that already defines the thinner portion of the 4FF sector. However, this technique is even more costly, owing to the molding process, and does not solve the aforementioned problems associated with the pre-cut lines.